OB fusion protein compositions and methods

ABSTRACT

The present invention relates to Fc-OB fusion protein compositions, methods of preparation of such compositions and uses thereof. In particular, the present invention relates to a genetic or chemical fusion protein comprising the Fc immunoglobulin region, derivative or analog fused to the N-terminal portion of the OB protein, derivative or analog.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 10/679,999,filed Oct. 6, 2003, now U.S. Pat. No. 6,936,439, which is a continuationof application Ser. No. 09/568,528, filed May 9, 2000 and now abandoned,which is a continuation of application Ser. No. 09/267,517, filed Mar.12, 1999 and now abandoned, which is a continuation of application Ser.No. 08/770,973, filed Dec. 20, 1996 and now abandoned. Application Ser.No. 09/568,528 is also a continuation-in-part of Ser. No. 09/094,931filed Jun. 15, 1998, and now abandoned, which is a continuation ofapplication Ser. No. 09/056,719, filed Apr. 7, 1998 and now abandoned,which is a continuation of application Ser. No. 08/561,732, filed Nov.22, 1995 and now abandoned. All of these applications are incorporatedby reference as if contained herein in their entirety.

FIELD OF THE INVENTION

The present invention relates to Fc-OB fusion protein compositions andmethods for preparation and use thereof.

BACKGROUND

Although the molecular basis for obesity is largely unknown, theidentification of the “OB gene” and protein encoded (“OB protein” or“leptin”) has shed some light on mechanisms the body uses to regulatebody fat deposition. See, PCT publication, WO 96/05309 (Dec. 22, 1996),Friedman et al.; Zhang et al., Nature 372: 425–432 (1994); see also, theCorrection at Nature 374: 479 (1995). The OB protein is active in vivoin both ob/ob mutant mice (mice obese due to a defect in the productionof the OB gene product) as well as in normal, wild type mice. Thebiological activity manifests itself in, among other things, weightloss. See generally, Barrinaga, “Obese” Protein Slims Mice, Science 269:475–456 (1995). The OB protein, derivatives and use thereof asmodulators for the control of weight and adiposity of animals, includingmammals and humans, has been disclosed in greater detail in PCTpublication WO 96/05309 (Dec. 22, 1996), hereby incorporated byreference, including figures.

The other biological effects of OB protein are not well characterized.It is known, for instance, that in ob/ob mutant mice, administration ofOB protein results in a decrease in serum insulin levels, and serumglucose levels. It is also known that administration of OB proteinresults in a decrease in body fat. This was observed in both ob/obmutant mice, as well as non-obese normal mice Pelleymounter et al.,Science 269: 540–543 (1995); Halaas et al., Science 269: 543–546 (1995).See also, Campfield et al., Science 269: 546–549 (1995) (Peripheral andcentral administration of microgram doses of OB protein reduced foodintake and body weight of ob/ob and diet-induced obese mice but not indb/db obese mice.) In none of these reports have toxicity's beenobserved, even at the highest doses.

Despite the promise of clinical application of the OB protein, the modeof action of the OB protein in vivo is not clearly elucidated.Information on the OB receptor, shows high affinity binding of the OBprotein detected in the rat hypothalamus, which indicates OB receptorlocation. Stephens et al., Nature 377: 530–532. The db/db mouse displaysthe identical phenotype as the ob/ob mouse, i.e., extreme obesity andType II diabetes; this phenotype is thought to be due to a defective OBreceptor, particularly since db/db mice fail to respond to OB proteinadministration. See Stephens et al., supra.

With the advances in recombinant DNA technologies, the availability ofrecombinant proteins for therapeutic use has engendered advances inprotein formulation and chemical modification. One goal of suchmodification is protein protection and decreased degradation. Fusionproteins and chemical attachment may effectively block a proteolyticenzyme from physical contact with the protein backbone itself, and thusprevent degradation. Additional advantages include, under certaincircumstances, increasing the stability, circulation time, and thebiological activity of the therapeutic protein. A review articledescribing protein modification and fusion proteins is Francis, Focus onGrowth Factors 3: 4–10 (May 1992) (published by Mediscript, MountviewCourt, Friern Barnet Lane, London N20, OLD, UK).

One such modification is the use of the Fc region of immunoglobulins.Antibodies comprise two functionally independent parts, a variabledomain known as “Fab”, which binds antigen, and a constant domain, knownas “Fc” which provides the link to effector functions such as complementor phagocytic cells. The Fc portion of an immunoglobulin has a longplasma half-life, whereas the Fab is short-lived. Capon, et al., Nature337: 525–531 (1989).

Therapeutic protein products have been constructed using the Fc domainto provide longer half-life or to incorporate functions such as Fcreceptor binding, protein A binding, complement fixation and placentaltransfer which all reside in the Fc proteins of immunoglobulins. Id. Forexample, the Fc region of an IgG1 antibody has been fused to theN-terminal end of CD30-L, a molecule which binds CD30 receptorsexpressed on Hodgkin's Disease tumor cells, anaplastic lymphoma cells,T-cell leukemia cells and other malignant cell types. See, U.S. Pat. No.5,480,981. IL-10, an anti-inflammatory and antirejection agent has beenfused to murine Fcγ2a in order to increase the cytokine's shortcirculating half-life. Zheng, X. et al., The Journal of Immunology, 154:5590–5600 (1995). Studies have also evaluated the use of tumor necrosisfactor receptor linked with the Fc protein of human IgG1 to treatpatients with septic shock. Fisher, C. et al., N. Engl. J. Med., 334:1697–1702 (1996); Van Zee, K. et al., The Journal of Immunology, 156:2221–2230 (1996). Fc has also been fused with CD4 receptor to produce atherapeutic protein for treatment of AIDS. See, Capon et al., Nature,337: 525–531 (1989). In addition, the N-terminus of interleukin 2 hasalso been fused to the Fc portion of IgG1 or IgG3 to overcome the shorthalf life of interleukin 2 and its systemic toxicity. See, Harvill etal., Immunotechnology, 1: 95–105 (1995).

Due to the identification of the OB protein as a promising therapeuticprotein, there exists a need to develop OB analog compositions forclinical application in conjunction with or in place of OB proteinadministration. Such development would include OB analog compositionswhere protein formulations and chemical modifications achieve decreasedprotein degradation, increased stability and circulation time. Thepresent invention provides such compositions.

SUMMARY OF THE INVENTION

The present invention relates to Fc-OB fusion protein compositions,methods of preparation of such compositions and uses thereof. Inparticular, the present invention relates to a genetic fusion proteincomprising the Fc region or analogs of immunoglobulins fused to theN-terminal portion of the OB protein or analogs. The Fc-OB fusionprotein is capable of dimerizing via the cysteine residues of the Fcregion. Unexpectedly, genetic fusion modification with Fc at theN-terminus of the OB protein demonstrates advantages in stability,clearance rate and decreased degradation which are not seen in OBprotein or with fusion of Fc to the C-terminus of the OB protein.Surprisingly and importantly, the N-terminus modification providesunexpected protein protection from degradation, increases circulationtime and stability, when compared to the OB protein or Fc modificationto the OB protein C-terminus. Such unexpected advantages from the Fcmodification to OB protein would be advantageous to OB proteinconsumers, in that these changes contribute to lower doses required orless frequent dosing. Thus, as described below in more detail, thepresent invention has a number of aspects relating to the geneticmodification of proteins via fusion of the Fc region to the OB protein(or analogs thereof), as well as, specific modifications, preparationsand methods of use thereof.

Accordingly, in one aspect, the present invention provides a Fc-OBfusion protein wherein Fc is genetically fused to the N-terminus of theOB protein (or analogs thereof). In addition, the Fc portion may also belinked to the N-terminus of the OB protein (or analogs thereof) viapeptide or chemical linkers as known in the art. As noted above anddescribed in more detail below, the Fc-OB fusion protein has unexpectedprotections from degradation and increased circulation time andstability when compared to the OB protein or C-terminus OB-Fc fusionproteins. Additional aspects of the present invention, therefore,include not only Fc-OB fusion protein compositions, but also DNAsequences encoding such proteins, related vectors and host cellscontaining such vectors, both useful for producing fusion proteins ofthe present invention.

In a second aspect, the present invention provides for preparing theFc-OB fusion protein. Such methods include recombinant DNA techniquesfor preparation of recombinant proteins. Furthermore, such aspectsinclude methods of fermentation and purification as well.

In another aspect, the present invention provides methods for treatingexcess weight in an individual or animals, including modulation ofand/or fat deposition by the administration of Fc-OB fusion proteins.Due to the Fc-OB fusion protein characteristics, methods arecontemplated which reduce the amount and/or frequency of dosage of OBprotein by using Fc-OB weight reducing agent.

In yet another aspect, the present invention provides for therapies forthe treatment or co-morbidities associated with excess fat, such asdiabetes, dys- or hyperlipidemias, arterial sclerosis, arterial plaque,the reduction or prevention of gall stones formation, stoke, and also anincrease in insulin sensitivity and/or an increase in lean tissue mass.

In another aspect, the present invention also provides for relatedpharmaceutical compositions of the Fc-OB proteins, analogs andderivatives thereof, for use in the above therapies.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 Recombinant murine metOB (double stranded) DNA (SEQ. ID. NOs.: 1and 2) and amino acid sequence (SEQ. ID. NO. 3).

FIG. 2 Recombinant human metOB analog (double stranded) DNA (SEQ. ID.NOs.: 4 and 5) and amino acid sequence (SEQ. ID. NO. 6).

FIG. 3(A–C) Recombinant human metFc-OB (double stranded) DNA (SEQ. ID.NOs.: 7 and 8) and amino acid sequence (SEQ. ID. NO. 9).

FIG. 4(A–C) Recombinant human metFc-OB variant (double stranded) DNA(SEQ. ID. NOs.: 10 and 11) and amino acid sequence (SEQ. ID. NO. 12).

FIG. 5(A–C) Recombinant human metFc-OB variant (double stranded) DNA(SEQ. ID. NOs.: 13 and 14) and amino acid sequence (SEQ. ID. NO. 15).

FIG. 6(A–C) Recombinant human metFc-OB variant (double stranded) DNA(SEQ. ID. NOs.: 16 and 17) and amino acid sequence (SEQ. ID. NO. 18).

DETAILED DESCRIPTION

The present invention relates to Fc-OB fusion protein compositions,methods of preparation of such compositions and uses thereof. Inparticular, the present invention relates to the genetic or chemicalfusion of the Fc region of immunoglobulins to the N-terminal portion ofthe OB protein. Unexpectedly, fusion of Fc at the N-terminus of the OBprotein demonstrates advantages which are not seen in OB protein or withfusion of Fc at the C-terminus of the OB protein. Surprisingly, theN-terminally modified Fc-OB protein provides unexpected proteinprotection from degradation, increased circulation time and increasedstability. Accordingly, the Fc-OB fusion protein, and analogs orderivatives thereof, as well as, related methods of use and preparation,are described in more detail below.

Compositions

The Fc sequence of the recombinant human Fc-OB sequence set forth inSEQ. ID. NO. 9 (See FIG. 3) may be selected from the humanimmunoglobulin IgG-1 heavy chain, see Ellison, J. W. et al., NucleicAcids Res. 10: 4071–4079 (1982), or any other Fc sequence known in theart (e.g. other IgG classes including but not limited to IgG-2, IgG-3and IgG-4, or other immunoglobulins). Variant, analogs or derivatives ofthe Fc portion may be constructed by, for example, making varioussubstitutions of residues or sequences.

Cysteine residues can be deleted or replaced with other amino acids toprevent formation of disulfide crosslinks of the Fc sequences. Inparticular amino acid at position 5 of SEQ. ID. NO. 9 is a cysteineresidue. The recombinant Fc-OB sequence of SEQ. ID. NO. 9 is a 378 aminoacid Fc-OB protein (not counting the methionine residue). The firstamino acid sequence for the recombinant Fc-OB protein of FIG. 3 isreferred to as +1 with the methionine at the −1 position.

One may remove the cysteine residue at position 5 or substitute it withone or more amino acids. An alanine residue may be substituted for thecysteine residue at position 6 giving the variant amino acid sequence ofFIG. 4 (SEQ. ID. NO. 12). The recombinant Fc-OB protein of FIG. 4 is a378 amino acid Fc-OB protein (not counting the methionine residue). Thefirst amino acid sequence for the recombinant Fc-OB protein of FIG. 4 isreferred to as +1 with the methionine at the −1 position.

Likewise, the cysteine at position 5 of SEQ. ID. NO. 9 could besubstituted with a serine or other amino acid residue or deleted. Avariant or analog may also be prepared by deletion of amino acids atpositions 1, 2, 3, 4 and 5 as with the variant in SEQ. ID. NO. 15 (SeeFIG. 5). Substitutions at these positions can also be made and are within the scope of this invention. The recombinant Fc-OB protein of FIG. 5is a 373 amino acid Fc-OB protein (not counting the methionine residue).The first amino acid sequence for the recombinant Fc-OB protein of FIG.5 is referred to as +1 with the methionine at the −1 position.

Modifications may also be made to introduce four amino acidsubstitutions to ablate the Fc receptor binding site and the complement(C1q) binding site. These variant modifications from SEQ. ID. NO. 15would include leucine at position 15 substituted with glutamate,glutamate at position 98 substituted with alanine, and lysines atpositions 100 and 102 substituted with alanines (see FIG. 6 and SEQ. ID.NO. 18). The recombinant Fc-OB protein of FIG. 6 is a 373 amino acidFc-OB protein (not counting the methionine residue). The first aminoacid sequence for the recombinant Fc-OB protein of FIG. 6 is referred toas +1 with the methionine at the −1 position.

Likewise, one or more tyrosine residues can be replaced by phenyalanineresidues as well. In addition, other variant amino acid insertions,deletions and/or substitutions are also contemplated and are within thescope of the present invention. Furthermore, alterations may be in theform of altered amino acids, such as peptidomimetics or D-amino acids.The Fc protein may be also linked to the OB proteins of the Fc-OBprotein by “linker” moieties whether chemical or amino acids of varyinglengths. Such chemical linkers are well known in the art. Amino acidlinker sequences can include but are not limited to:

(a) ala, ala, ala;

(b) ala, ala, ala, ala;

(c) ala, ala, ala, ala, ala;

(d) gly, gly;

(e) gly, gly, gly;

(f) gly, gly, gly, gly, gly;

(g) gly, gly, gly, gly, gly, gly, gly;

(h) gly-pro-gly;

(i) gly, gly, pro, gly, gly; and

(j) any combination of subparts (a) through (i).

The OB portion of the Fc-OB fusion protein may be selected from therecombinant murine set forth in SEQ. ID. NO. 3 (See FIG. 1), or therecombinant human protein as set forth in Zhang et al., Nature, supra,(herein incorporated by reference) or those lacking a glutaminyl residueat position 28. (See Zhang et al, Nature, supra, at page 428.) One mayalso use the recombinant human OB protein analog as set forth in SEQ.ID. NO. 6 (See FIG. 2), which contains: (1) an arginine in place oflysine at position 35; and (2) a leucine in place of isoleucine atposition 74. (A shorthand abbreviation for this analog is therecombinant human R->L³⁵, I->L⁷⁴). The amino acid sequences for therecombinant human and recombinant murine proteins or analogs with orwithout the fused Fc portion at the N-terminus of the OB protein are setforth below with a methionyl residue at the −1 position; however, aswith any of the present OB proteins and analogs, the methionyl residuemay be absent.

The murine protein is substantially homologous to the human protein,particularly as a mature protein, and, further, particularly at theN-terminus. One may prepare an analog of the recombinant human proteinby altering (such as substituting amino acid residues), in therecombinant human sequence, the amino acids which, diverge from themurine sequence. Because the recombinant human protein has biologicalactivity in mice, such an analog would likely be active in humans. Forexample, using a human protein having a lysine at residue 35 and anisoleucine at residue 74 according to the numbering of SEQ. ID. NO. 6,wherein the first amino acid is valine, and the amino acid at position146 is cysteine, one may substitute with another amino acid one or moreof the amino acids at positions 32, 35, 50, 64, 68, 71, 74, 77, 89, 97,100, 105, 106, 107, 108, 111, 118, 136, 138, 142, and 145. One mayselect the amino acid at the corresponding position of the murineprotein, (SEQ. ID. NO. 3), or another amino acid.

One may further prepare “consensus” molecules based on the rat OBprotein sequence. Murakami et al., Biochem. Biophys. Res. Comm. 209:944–952 (1995) herein incorporated by reference. Rat OB protein differsfrom human OB protein at the following positions (using the numbering ofSEQ. ID. NO. 6): 4, 32, 33, 35, 50, 68, 71, 74, 77, 78, 89, 97, 100,101, 102, 105, 106, 107, 108, 111, 118, 136, 138and 145. One maysubstitute with another amino acid one or more of the amino acids atthese divergent positions. The positions in bold print are those inwhich the murine OB protein as well as the rat OB protein are divergentfrom the human OB protein, and thus, are particularly suitable foralteration. At one or more of a positions, one may substitute an aminoacid from the corresponding rat OB protein, or another amino acid.

The positions from both rat and murine OB protein which diverge from themature human OB protein are: 4, 32, 33, 35, 50, 64, 68, 71, 74, 77, 78,89, 97, 100, 102, 105, 106, 107, 108, 111, 118, 136, 138, 142, and 145.An OB protein according to SEQ. ID. NO. 6 having one or more of theabove amino acids replaced with another amino acid, such as the aminoacid found in the corresponding rat or murine sequence, may also beeffective.

In addition, the amino acids found in rhesus monkey OB protein whichdiverge from the mature human OB protein are (with identities noted inparentheses in one letter amino acid abbreviation): 8 (S), 35 (R),48(V), 53(a), 60(I), 66(I), 67(N), 68((L), 89(L), 100(L), 108(E), 112(D), and 118 (L). Since the recombinant human OB protein is active incynomolgus monkeys, a human OB protein according to SEQ. ID. NO. 6 (withlysine at position 35 and isoleucine at position 74) having one or moreof the rhesus monkey divergent amino acids replaced with another aminoacid, such as the amino acids in parentheses, may be effective. Itshould be noted that certain rhesus divergent amino acids are also thosefound in the above murine species (positions 35, 68, 89, 100 and 112).Thus, one may prepare a murine/rhesus/human consensus molecule having(using the numbering of SEQ. ID. NO. 6 having a lysine at position 35and an isoleucine at position 74) having one or more of the amino acidsat positions replaced by another amino acid: 4, 8, 32, 33, 35, 48, 50,53, 60, 64, 66, 67, 68, 71, 74, 77, 78, 89, 97, 100, 102, 105, 106, 107,108, 111, 112, 118, 136, 138, 142, and 145.

Other analogs may be prepared by deleting a part of the protein aminoacid sequence. For example, the, mature protein lacks a leader sequence(−22 to −1). One may prepare the following truncated forms of human OBprotein molecules (using the numbering of SEQ. ID. NO. 6):

(a) amino acids 98–146

(b) amino acids 1–32

(c) amino acids 40–116

(d) amino acids 1–99 and (connected to) 112–146

(e) amino acids 1–99 and (connected to) 112–146 having one or more ofamino acids 100–111 placed between amino acids 99 and 112.

In addition, the truncated forms may also have altered one or more ofthe amino acids which are divergent (in the rat, murine, or rhesus OBprotein) from human OB protein. Furthermore, any alterations may be inthe form of altered amino acids, such as peptidomimetics or D-aminoacids.

Therefore, the present invention encompasses a Fc-OB fusion proteinwherein the OB protein is selected from:

(a) the amino acid sequence 1–146 as set forth in SEQ. ID. NO. 3 (below)or SEQ. ID. NO. 6;

(b) the amino acid sequence 1–146 as set forth in SEQ. ID. NO. 6 havinga lysine residue at position 35 and an isoleucine residue at position74;

(c) the amino acid sequence of subpart (b) having a different amino acidsubstituted in one or more of the following positions (using thenumbering according to SEQ. ID. NO. 6 and retaining the same numberingeven in the absence of a glutaminyl residue at position 28): 4, 32, 33,35, 50, 64, 68, 71, 74, 77, 78, 89, 97, 100, 102, 105, 106, 107, 108,111, 118, 136, 138, 142, and 145;

(d) the amino acid sequence of subparts (a), (b) or (c) optionallylacking a glutaminyl residue at position 28;

(e) the amino acid sequence or subparts (a), (b), (c), or (d) having amethionyl residue at the N-terminus;

(f) a truncated OB protein analog selected from among: (using thenumbering of SEQ. ID. NO. 6):

-   -   (i) amino acids 98–146    -   (ii) amino acids 1–32    -   (iii) amino acids 40–116    -   (iv) amino acids 1–99 and 112–146    -   (v) amino acids 1–99 and 112–146 having one or more of amino        acids 100–111 placed between amino acids 99 and 112; and,    -   (vi) the truncated OB analog of subpart (i) having one or more        of amino acids 100, 102, 105, 106, 107, 108, 111, 118, 136, 138,        142, and 145 substituted with another amino acid;    -   (vii) the truncated analog of subpart (ii) having one or more of        amino acids 4, 8 and 32 substituted with another amino acid;    -   (viii) the truncated analog of subpart (iii) having one or more        of amino acids 50, 53, 60, 64, 66, 67, 68, 71, 74, 77, 78, 89,        97, 100, 102, 105, 106, 107, 108, 111 and 112 replaced with        another amino acid;    -   (vix) the truncated analog of subpart (iv) having one or more of        amino acids 4, 8, 32, 33, 35, 48, 50, 53, 60, 64, 66, 67, 68,        71, 74, 77, 78, 89, 97, 112, 118, 136, 138, 142, and 145        replaced with another amino acid; and    -   (x) the truncated analog of subpart (v) having one or more of        amino acids 4, 32, 33, 35, 50, 64, 68, 71, 74, 77, 78, 89, 97,        100, 102, 105, 106, 107, 108, 111, 118, 136, 138, 142, and 145        replaced with another amino acid;    -   (xi) the truncated analog of any of subparts (i)–(x) having an        N-terminal methionyl residue; and

(g) the OB protein or analog derivative of any of subparts (a) through(f) comprised of a chemical moiety connected to the protein moiety;

(h) a derivative of subpart (g) wherein said chemical moiety is a watersoluble polymer moiety;

(i) a derivative of subpart (h) wherein said water soluble polymermoiety is polyethylene glycol;

(j) a derivative of subpart (h) wherein said water soluble polymermoiety is a polyaminoacid moiety;

(k) a derivative of subpart (h) through (j) wherein said moiety isattached at solely the N-terminus of said protein moiety; and

(l) an OB protein, analog or derivative of any of subparts (a) through(k) in a pharmaceutically acceptable carrier.

Derivatives

The present Fc-OB fusion proteins (herein the term “protein” is used toinclude “peptide,” Fc, OB or analogs, such as those recited infra,unless otherwise indicated) are derivatized by the attachment of one ormore chemical moieties to the Fc-OB fusion protein moiety. Thesechemically modified derivatives may be further formulated forintraarterial, intraperitoneal, intramuscular subcutaneous, intravenous,oral, nasal, pulmonary, topical or other routes of administration asdiscussed below. Chemical modification of biologically active proteinshas been found to provide additional advantages under certaincircumstances, such as increasing the stability and circulation time ofthe therapeutic protein and decreasing immunogenicity. See, U.S. Pat.No. 4,179,337, Davis et al., issued Dec. 18, 1979. For a review, seeAbuchowski et al., in Enzymes as Drugs. (J. S. Holcerberg and J.Roberts, eds. pp. 367–383 (1981)); Francis et al., supra.

The chemical moieties suitable for such derivatization may be selectedfrom among various water soluble polymers. The polymer selected shouldbe water soluble so that the protein to which it is attached does notprecipitate in an aqueous environment, such as a physiologicalenvironment. Preferably, for therapeutic use of the end-productpreparation, the polymer will be pharmaceutically acceptable. Oneskilled in the art will be able to select the desired polymer based onsuch considerations as whether the polymer/protein conjugate will beused therapeutically, and if so, the desired dosage, circulation time,resistance to proteolysis, and other considerations. For the presentproteins and peptides, the effectiveness of the derivatization may beascertained by administering the derivative, in the desired form (i.e.,by osmotic pump, or, more preferably, by injection or infusion, or,further formulated for oral, pulmonary or nasal delivery, for example),and observing biological effects as described herein.

The water soluble polymer may be selected from the group consisting of,for example, polyethylene glycol, copolymers of ethyleneglycol/propylene glycol, carboxymethylcellulose, dextran, polyvinylalcohol, polyvinyl pyrolidone, poly-1,3-dioxolane, poly-1,3,6-trioxane,ethylene/maleic anhydride copolymer, polyaminoacids (either homopolymersor random copolymers), and dextran or poly(n-vinylpyrolidone)polyethylene glycol, propylene glycol homopolymers,polypropylene oxide/ethylene oxide co-polymers, polyoxyethylated polyolsand polyvinyl alcohol. Polyethylene glycol propionaldenhyde may haveadvantages in manufacturing due to its stability in water. Also,succinate and styrene may also be used.

The OB or Fc proteins used to formulate the Fc-OB fusion protein, may beprepared by attaching polyaminoacids or branch point amino acids to theFc or OB protein (or analogs) moiety. For example, the polyaminoacid maybe an additional carrier protein which, like the Fc fused to the OBprotein or OB analog of the present invention, serves to also increasethe circulation half life of the protein in addition to the advantagesachieved via the Fc-OB fusion protein above. For the present therapeuticor cosmetic purpose of the present invention, such polyaminoacids shouldbe those which have or do not create neutralizing antigenic response, orother adverse responses. Such polyaminoacids may be selected from thegroup consisting of serum album (such as human serum albumin), anadditional antibody or portion thereof (e.g. the Fc region), or otherpolyaminoacids, e.g. lysines. As indicated below, the location ofattachment of the polyaminoacid may be at the N-terminus of the Fc-OBprotein moiety, or C-terminus, or other places in between, and also maybe connected by a chemical “linker” moiety to the Fc-OB protein.

The polymer may be of any molecular weight, and may be branched orunbranched. For polyethylene glycol, the preferred molecular weight isbetween about 2 kDa and about 100 kDa (the term “about” indicating thatin preparations of polyethylene glycol, some molecules will weigh more,some less, than the stated molecular weight) for ease in handling andmanufacturing. Other sizes may be used, depending on the desiredtherapeutic profile (e.g., the duration of sustained release desired,the effects, if any on biological activity, the ease in handling, thedegree or lack of antigenicity and other known effects of thepolyethylene glycol to a therapeutic protein or analog).

The number of polymer molecules so attached may vary, and one skilled inthe art will be able to ascertain the effect on function. One maymono-derivatize, or may provide for a di-, tri-, tetra- or somecombination of derivatization, with the same or different chemicalmoieties (e.g., polymers, such as different weights of polyethyleneglycols). The proportion of polymer molecules to protein (or peptide)molecules will vary, as will their concentrations in the reactionmixture. In general, the optimum ratio (in terms of efficiency ofreaction in that there is no excess unreacted protein or polymer) willbe determined by factors such as the desired degree of derivatization(e.g., mono, di-, tri-, etc.), the molecular weight of the polymerselected, whether the polymer is branched or unbranched, and thereaction conditions.

The chemical moieties should be attached to the protein withconsideration of effects on functional or antigenic domains of theprotein. There are a number of attachment methods available to thoseskilled in the art. E.g., EP 0 401 384 herein incorporated by reference(coupling PEG to G-CSF), see also Malik et al., Exp. Hematol. 20:1028–1035 (1992) (reporting pegylation of GM-CSF using tresyl chloride).For example, polyethylene glycol may be covalently bound through aminoacid residues via a reactive group, such as, a free amino or carboxylgroup. Reactive groups are those to which an activated polyethyleneglycol molecule may be bound. The amino acid residues having a freeamino group may include lysine residues and the N-terminal amino acidresidue. Those having a free carboxyl group may include aspartic acidresidues, glutamic acid residues, and the C-terminal amino acid residue.Sulfhydryl groups may also be used as a reactive group for attaching thepolyethylene glycol molecule(s). Preferred for therapeutic purposes isattachment at an amino group, such as attachment at the N-terminus orlysine group. Attachment at residues important for receptor bindingshould be avoided if receptor binding is desired.

One may specifically desire N-terminally chemically modified Fc-OBfusion protein. Using polyethylene glycol as an illustration of thepresent compositions, one may select from a variety of polyethyleneglycol molecules (by molecular weight, branching, etc.), the proportionof polyethylene glycol molecules to protein (or peptide) molecules inthe reaction mix, the type of pegylation reaction to be performed, andthe method of obtaining the selected N-terminally pegylated protein. Themethod of obtaining the N-terminally pegylated preparation (i.e.,separating this moiety from other monopegylated moieties if necessary)may be by purification of the N-terminally pegylated material from apopulation of pegylated protein molecules. Selective N-terminal chemicalmodification may be accomplished by reductive alkylation which exploitsdifferential reactivity of different types of primary amino groups(lysine versus the N-terminal) available for derivatization in aparticular protein. Under the appropriate reaction conditions,substantially selective derivatization of the protein at the N-terminuswith a carbonyl group containing polymer is achieved. For example, onemay selectively N-terminally pegylate the protein by performing thereaction at a pH which allows one to take advantage of the pK_(a)differences between the ε-amino group of the lysine residues and that ofthe α-amino group of the N-terminal residue of the protein. By suchselective derivatization, attachment of a water soluble polymer to aprotein is controlled: the conjugation with the polymer takes placepredominantly at the N-terminus of the protein and no significantmodification of other reactive groups, such as the lysine side chainamino groups, occurs. Using reductive alkylation, the water solublepolymer may be of the type described above, and should have a singlereactive aldehyde for coupling to the protein. Polyethylene glycolpropionaldehyde, containing a single reactive aldehyde, may be used.

An N-terminally monopegylated derivative is preferred for ease inproduction of a therapeutic. N-terminal pegylation ensures a homogenousproduct as characterization of the product is simplified relative todi-, tri- or other multi-pegylated products. The use of the abovereductive alkylation process for preparation of an N-terminal product ispreferred for ease in commercial manufacturing.

Complexes

The Fc-OB fusion protein, analog or derivative thereof may beadministered complexed to a binding composition. Such bindingcomposition may have the effect of prolonging the circulation time evenfurther than that achieved with the Fc-OB fusion protein, analog orderivative. Such composition may be a protein (or synonymously,peptide). An example of a binding protein is OB protein receptor orportion thereof, such as a soluble portion thereof. Other bindingproteins may be ascertained by examining OB protein or Fc-OB protein inserum, or by empirically screening for the presence of binding. Bindingproteins used will typically not interfere with the ability of OBprotein, Fc-OB fusion proteins, or analogs or derivatives thereof, tobind to endogenous OB protein receptor and/or effect signaltransduction.

Pharmaceutical Compositions

The present invention also provides methods of using pharmaceuticalcompositions of the Fc-OB fusion proteins and derivatives. Suchpharmaceutical compositions may be for administration for injection, orfor oral, pulmonary, nasal, transdermal or other forms ofadministration. In general, comprehended by the invention arepharmaceutical compositions comprising effective amounts of protein orderivative products of the invention together with pharmaceuticallyacceptable diluents, preservatives, solubilizers, emulsifiers, adjuvantsand/or carriers. Such compositions include diluents of various buffercontent (e.g., Tris-HCl, acetate, phosphate), pH and ionic strength;additives such as detergents and solubilizing agents (e.g., Tween 80,Polysorbate 80), anti-oxidants (e.g., ascorbic acid, sodiummetabisulfite), preservatives (e.g., Thimersol, benzyl alcohol) andbulking substances (e.g., lactose, mannitol); incorporation of thematerial into particulate preparations of polymeric compounds such aspolylactic acid, polyglycolic acid, etc. or into liposomes. Hylauronicacid may also be used, and this may have the effect of promotingsustained duration in the circulation. Such compositions may influencethe physical state, stability, rate of in vivo release, and rate of invivo clearance of the present proteins and derivatives. See, e.g.,Remington's Pharmaceutical Sciences, 18th Ed. (1990, Mack PublishingCo., Easton, Pa. 18042) pages 1435–1712 which are herein incorporated byreference. The compositions may be prepared in liquid form, or may be indried powder, such as lyophilized form. Implantable sustained releaseformulations are also contemplated, as are transdermal formulations.

Contemplated for use herein are oral solid dosage forms, which aredescribed generally in Remington's Pharmaceutical Sciences, 18th Ed.1990 (Mack Publishing Co. Easton Pa. 18042) at Chapter 89, which isherein incorporated by reference. Solid dosage forms include tablets,capsules, pills, troches or lozenges, cachets or pellets. Also,liposomal or proteinoid encapsulation may be used to formulate thepresent compositions (as, for example, proteinoid microspheres reportedin U.S. Pat. No. 4,925,673). Liposomal encapsulation may be used and theliposomes may be derivatized with various polymers (e.g., U.S. Pat. No.5,013,556). A description of possible solid dosage forms for thetherapeutic is given by Marshall, K. In: Modern Pharmaceutics Edited byG. S. Banker and C. T. Rhodes Chapter 10, 1979, herein incorporated byreference. In general, the formulation will include the Fc-OB fusionprotein (or analog or derivative), and inert ingredients which allow forprotection against the stomach environment, and release of thebiologically active material in the intestine.

Also specifically contemplated are oral dosage forms of the abovederivatized proteins. Fc-OB fusion protein may be chemically modified sothat oral delivery of the derivative is efficacious. Generally, thechemical modification contemplated is the attachment of at least onemoiety to the protein (or peptide) molecule itself, where said moietypermits (a) inhibition of proteolysis; and (b) uptake into the bloodstream from the stomach or intestine. Also desired is the increase inoverall stability of the protein and increase in circulation time in thebody. Examples of such moieties include: Polyethylene glycol, copolymersof ethylene glycol and propylene glycol, carboxymethyl cellulose,dextran, polyvinyl alcohol, polyvinyl pyrrolidone and polyproline.Abuchowski and Davis, Soluble Polymer-Enzyme Adducts. In: “Enzymes asDrugs”, Hocenberg and Roberts, eds., Wiley-Interscience, New York, N.Y.,(1981), pp 367–383; Newmark, et al., J. Appl. Biochem. 4: 185–189(1982). Other polymers that could be used are poly-1,3-dioxolane andpoly-1,3,6-tioxocane. Preferred for pharmaceutical usage, as indicatedabove, are polyethylene glycol moieties.

For the Fc-OB fusion protein, analog or derivative, the location ofrelease may be the stomach, the small intestine (e.g., the duodenum,jejunum, or ileum), or the large intestine. One skilled in the art hasavailable formulations which will not dissolve in the stomach, yet willrelease the material in the duodenum or elsewhere in the intestine.Preferably, the release will avoid the deleterious effects of thestomach environment, either by protection of the Fc-OB fusion protein,analog or derivative, or by release of the biologically active materialbeyond the stomach environment, such as in the intestine.

To ensure full gastric resistance a coating impermeable to at least pH5.0 is essential. Examples of the more common inert ingredients that areused as enteric coatings are cellulose acetate trimellitate (CAT),hydroxypropylmethylcellulose phthalate (HPMCP), HPMCP 50, HPMCP 55,polyvinyl acetate phthalate (PVAP), Eudragit L30D, Aquateric, celluloseacetate phthalate (CAP), Eudragit L, Eudragit S, and Shellac. Thesecoatings may be used as mixed films.

A coating or mixture of coatings can also be used on tablets, which arenot intended for protection against the stomach. This can include sugarcoatings, or coatings which make the tablet easier to swallow. Capsulesmay consist of a hard shell (such as gelatin) for delivery of drytherapeutic i.e. powder; for liquid forms, a soft gelatin shell may beused. The shell material of cachets could be thick starch or otheredible paper. For pills, lozenges, molded tablets or tablet triturates,moist massing techniques can be used.

The therapeutic can be included in the formulation as finemultiparticulates in the form of granules or pellets of particle sizeabout 1 mm. The formulation of the material for capsule administrationcould also be as a powder, lightly compressed plugs or even as tablets.The therapeutic could be prepared by compression.

Colorants and flavoring agents may all be included. For example, theprotein (or derivative) may be formulated (such as by liposome ormicrosphere encapsulation) and then further contained within an edibleproduct, such as a refrigerated beverage containing colorants andflavoring agents.

One may dilute or increase the volume of the therapeutic with an inertmaterial. These diluents could include carbohydrates, especiallymannitol, α-lactose, anhydrous lactose, cellulose, sucrose, modifieddextrans and starch. Certain inorganic salts may be also be used asfillers including calcium triphosphate, magnesium carbonate and sodiumchloride. Some commercially available diluents are Fast-Flo, Emdex,STA-Rx 1500, Emcompress and Avicell.

Disintegrants may be included in the formulation of the therapeutic intoa solid dosage form. Materials used as disintegrates include but are notlimited to starch including the commercial disintegrant based on starch,Explotab. Sodium starch glycolate, Amberlite, sodiumcarboxymethylcellulose, ultramylopectin, sodium alginate, gelatin,orange peel, acid carboxymethyl cellulose, natural sponge and bentonitemay all be used. Another form of the disintegrants are the insolublecationic exchange resins. Powdered gums may be used as disintegrants andas binders and these can include powdered gums such as agar, Karaya ortragacanth. Alginic acid and its sodium salt are also useful asdisintegrants.

Binders may be used to hold the therapeutic agent together to form ahard tablet and include materials from natural products such as acacia,tragacanth, starch and gelatin. Others include methyl cellulose (MC),ethyl cellulose (EC) and carboxymethyl cellulose (CMC). Polyvinylpyrrolidone (PVP) and hydroxypropylmethyl cellulose (HPMC) could both beused in alcoholic solutions to granulate the therapeutic.

An antifrictional agent may be included in the formulation of thetherapeutic to prevent sticking during the formulation process.Lubricants may be used as a layer between the therapeutic and the diewall, and these can include but are not limited to; stearic acidincluding its magnesium and calcium salts, polytetrafluoroethylene(PTFE), liquid paraffin, vegetable oils and waxes. Soluble lubricantsmay also be used such as sodium lauryl sulfate, magnesium laurylsulfate, polyethylene glycol of various molecular weights, Carbowax 4000and 6000.

Glidants that might improve the flow properties of the drug duringformulation and to aid rearrangement during compression might be added.The glidants may include starch, talc, pyrogenic silica and hydratedsilicoaluminate.

To aid dissolution of the therapeutic into the aqueous environment asurfactant might be added as a wetting agent. Surfactants may includeanionic detergents such as sodium lauryl sulfate, dioctyl sodiumsulfosuccinate and dioctyl sodium sulfonate. Cationic detergents mightbe used and could include benzalkonium chloride or benzethomiumchloride. The list of potential nonionic detergents that could beincluded in the formulation as surfactants are lauromacrogol 400,polyoxyl 40 stearate, polyoxyethylene hydrogenated castor oil 10, 50 and60, glycerol monostearate, polysorbate 40, 60, 65 and 80, sucrose fattyacid ester, methyl cellulose and carboxymethyl cellulose. Thesesurfactants could be present in the formulation of the protein orderivative either alone or as a mixture in different ratios.

Additives which potentially enhance uptake of the protein (orderivative) are for instance the fatty acids oleic acid, linoleic acidand linolenic acid.

Controlled release formulation may be desirable. The drug could beincorporated into an inert matrix which permits release by eitherdiffusion or leaching mechanisms e.g., gums. Slowly degeneratingmatrices may also be incorporated into the formulation, e.g., alginates,polysaccahrides. Another form of a controlled release of thistherapeutic is by a method based on the Oros therapeutic system (AlzaCorp.), i.e., the drug is enclosed in a semipermeable membrane whichallows water to enter and push drug out through a single small openingdue to osmotic effects. Some enteric coatings also have a delayedrelease effect.

Other coatings may be used for the formulation. These include a varietyof sugars which could be applied in a coating pan. The therapeutic agentcould also be given in a film coated tablet and the materials used inthis instance are divided into 2 groups. The first are the nonentericmaterials and include methyl cellulose, ethyl cellulose, hydroxyethylcellulose, methylhydroxy-ethyl cellulose, hydroxypropyl cellulose,hydroxypropyl-methyl cellulose, sodium carboxy-methyl cellulose,providone and the polyethylene glycols. The second group consists of theenteric materials that are commonly esters of phthalic acid.

A mix of materials might be used to provide the optimum film coating.Film coating may be carried out in a pan coater or in a fluidized bed orby compression coating.

Also contemplated herein is pulmonary delivery of the present protein(or derivatives thereof). The protein (or derivative) is delivered tothe lungs of a manual while inhaling and traverses across the lungepithelial lining to the blood stream. (Other reports of this includeAdjei et al., Pharmaceutical Research 7: 565–569 (1990); Adjei et al.,International Journal of Pharmaceutics 63: 135–144 (1990)(leuprolideacetate); Braquet et al., Journal of Cardiovascular Pharmacology 13(suppl. 5): s. 143–146 (1989)(endothelin-1); Hubbard et al., Annals ofInternal Medicine 3: 206–212 (1989) (α1-antitrypsin); Smith et al., J.Clin. Invest. 84: 0.1145–1146 (1989)(α-1-proteinase); Oswein et al.,“Aerosolization of Proteins”, Proceedings of Symposium on RespiratoryDrug Delivery II, Keystone, Colo., March, 1990 (recombinant human growthhormone); Debs et al., The Journal of Immunology 140: 3482–3488 (1988)(interferon-γ and tumor necrosis factor α) and Platz et al. U.S. Pat.No. 5,284,656 (granulocyte colony stimulating factor).

Contemplated for use in the practice of this invention are a wide rangeof mechanical devices designed for pulmonary delivery of therapeuticproducts, including but not limited to nebulizers, metered doseinhalers, and powder inhalers, all of which are familiar to thoseskilled in the art.

Some specific examples of commercially available devices suitable forthe practice of this invention are the Ultravent nebulizer, manufacturedby Mallinckrodt, Inc., St. Louis, Mo.; the Acorn II nebulizer,manufactured by Marquest Medical Products, Englewood, Colo.; theVentolin metered dose inhaler, manufactured by Glaxo Inc., ResearchTriangle Park, N.C.; and the Spinhaler powder inhaler, manufactured byFisons Corp., Bedford, Mass.

All such devices require the use of formulations suitable for thedispensing of protein (or analog or derivative). Typically, eachformulation is specific to the type of device employed and may involvethe use of an appropriate propellant material, in addition to diluents,adjuvants and/or carriers useful in therapy.

The protein (or derivative) should most advantageously be prepared inparticulate form with an average particle size of less than 10 μm (ormicrons), most preferably 0.5 to 5 μm, for most effective delivery tothe distal lung.

Carriers include carbohydrates such as trehalose, mannitol, xylitol,sucrose, lactose, and sorbitol. Other ingredients for use informulations may include DPPC, DOPE, DSPC and DOPC. Natural or syntheticsurfactants may be used. Polyethylene glycol may be used (even apartfrom its use in derivatizing the protein or analog). Dextrans, such ascyclodextran, may be used. Bile salts and other related enhancers may beused. Cellulose and cellulose derivatives may be used. Amino acids maybe used, such as use in a buffer formulation.

Also, the use of liposomes, microcapsules or microspheres, inclusioncomplexes, or other types of carriers is contemplated.

Formulations suitable for use with a nebulizer, either jet orultrasonic, will typically comprise Fc-OB protein, analogs orderivatives thereof, dissolved in water at a concentration of about 0.1to 25 mg of biologically active protein per mL of solution. Theformulation may also include a buffer and a simple sugar (e.g., forprotein stabilization and regulation of osmotic pressure). The nebulizerformulation may also contain a surfactant, to reduce or prevent surfaceinduced aggregation of the protein caused by atomization of the solutionin forming the aerosol.

Formulations for use with a metered-dose inhaler device will generallycomprise a finely divided powder containing the protein (or derivative)suspended in a propellant with the aid of a surfactant. The propellantmay be any conventional material employed for this purpose, such as achlorofluorocarbon, a hydrochlorofluorocarbon, a hydrofluorocarbon, or ahydrocarbon, including trichlorofluoromethane, dichlorodifluoromethane,dichlorotetrafluoroethanol, and 1,1,1,2-tetrafluoroethane, orcombinations thereof. Suitable surfactants include sorbitan trioleateand soya lecithin. Oleic acid may also be useful as a surfactant.

Formulations for dispensing from a powder inhaler device will comprise afinely divided dry powder containing protein (or derivative) and mayalso include a bulking agent, such as lactose, sorbitol, sucrose,mannitol, trehalose, or xylitol in amounts which facilitate dispersal ofthe powder from the device, e.g., 50 to 90% by weight of theformulation.

Nasal delivery of the protein (or analog or derivative) is alsocontemplated. Nasal delivery allows the passage of the protein to theblood stream directly after administering the therapeutic product to thenose, without the necessity for deposition of the product in the lung.Formulations for nasal delivery include those with dextran orcyclodextran. Delivery via transport across other mucus membranes isalso contemplated.

Dosage

One skilled in the art will be able to ascertain effective dosages byadministration and observing the desired therapeutic effect. Due to theN-terminus modification of the OB protein, the present inventionprovides unexpected protein protection from degradation, and increasescirculation time and stability, when compared to OB protein orC-terminus modification of the OB protein. One skilled in the art,therefore, will be able to ascertain from these changes that aneffective dosage may require lower doses or less frequent dosing.

Preferably, the formulation of the molecule will be such that betweenabout 0.10 μg/kg/day and 10 mg/kg/day will yield the desired therapeuticeffect. The effective dosages may be determined using diagnostic toolsover time. For example, a diagnostic for measuring the amount of OBprotein or Fc-OB fusion protein in the blood (or plasma or serum) mayfirst be used to determine endogenous levels of protein. Such diagnostictools may be in the form of an antibody assay, such as an antibodysandwich assay. The amount of endogenous OB protein is quantifiedinitially, and a baseline is determined. The therapeutic dosages aredetermined as the quantification of endogenous and exogenous OB proteinor Fc-OB fusion protein (that is, protein, analog or derivative foundwithin the body, either self-produced or administered) is continued overthe course of therapy. The dosages may therefore vary over the course oftherapy, with a relatively high dosage being used initially, untiltherapeutic benefit is seen, and lower dosages used to maintain thetherapeutic benefits.

Ideally, in situations where solely reduction in blood lipid levels isdesired, where maintenance of reduction of blood lipid levels isdesired, or an increase in lean body mass is desired, the dosage will beinsufficient to result in weight loss. Thus, during an initial course oftherapy of an obese person, dosages may be administered whereby weightloss and concomitant blood lipid level lowering or concomitant fattissue decrease/lean mass increase is achieved. Once sufficient weightloss is achieved, a dosage sufficient to prevent re-gaining weight, yetsufficient to maintain desired blood lipid levels or lean mass increase(or, prevention of lean mass depletion) may be administered. Thesedosages can be determined empirically, as the effects of OB or Fc-OBprotein are reversible, (e.g., Campfield et al., Science 269: 546–549(1995) at 547). Thus, if a dosage resulting in weight loss is observedwhen weight loss is not desired, one would administer a lower dose inorder to achieve the desired blood lipid levels or increase in leantissue mass, yet maintain the desired weight.

For increasing an individual's sensitivity to insulin, similar dosageconsiderations may be taken into account. Lean mass increase withoutweight loss may be achieved sufficient to decrease the amount of insulin(or, potentially, amylin, thiazolidinediones, or other potentialdiabetes treating drugs) an individual would be administered for thetreatment of diabetes.

For increasing overall strength, there may be similar dosageconsiderations. Lean mass increase with concomitant increase in overallstrength may be achieved with doses insufficient to result in weightloss. Other benefits, such as an increase in red blood cells (andoxygenation in the blood) and a decrease in bone resorption orosteoporosis may also be achieved in the absence of weight loss.

Combinations

The present methods may be used in conjunction with other medicaments,such as those useful for the treatment of diabetes (e.g., insulin,possibly, thiazolidinediones, amylin, or antagonists thereof),cholesterol and blood pressure lowering medicaments (such as those whichreduce blood lipid levels or other cardiovascular medicaments), andactivity increasing medicaments (e.g., amphetamines). Appetitesuppressants may also be used (such as those affecting the levels ofserotonin or neuropeptide Y). Such administration may be simultaneous ormay be in seriatim.

In addition, the present methods may be used in conjunction withsurgical procedures, such as cosmetic surgeries designed to alter theoverall appearance of a body (e.g., liposuction or laser surgeriesdesigned to reduce body mass). The health benefits of cardiac surgeries,such as bypass surgeries or other surgeries designed to relieve adeleterious condition caused by blockage of blood vessels by fattydeposits, such as arterial plaque, may be increased with concomitant useof the present compositions and methods. Methods to eliminate gallstones, such as ultrasonic or laser methods, may also be used eitherprior to, during or after a course of the present therapeutic methods.Furthermore, the present methods may be used as an adjunct to surgeriesor therapies for broken bones, damaged muscle, or other therapies whichwould be improved by an increase in lean tissue mass.

The following examples are offered to more fully illustrate theinvention, but are not to be construed as limiting the scope thereof.

EXAMPLE 1 Use of Murine FC-OB Protein Via Subcutaneous Injection

This example demonstrates that injection subcutaneously of murine Fc-OBprotein results in weight loss in normal mice. Normal (non-obese) CD1mice were administered murine Fc-OB protein via subcutaneous injectionsover a 22 day time period. A dosage of 10 mg protein/kg body weight/dayresulted in a 14% (+/−1.1%) loss from baseline weight by the 22nd day ofinjections. A dosage of PBS resulted in a 3.9% (+/−3.3%) loss frombaseline weight by the 22nd day of injections. The weight loss with theuse of 10 mg protein/kg body weight/day of Fc-OB protein in obese CD1mice resulted in a 10% (+/−4.3%) loss from baseline weight and a dosageof PBS resulted in a 8.7% (+/−1.3%) loss from baseline weight, both bythe 22nd day of injections.

Presented below are the percent (%) differences from baseline weight inCD1 mice (8 weeks old):

TABLE 1 Weight Loss Upon Subcutaneous Injection Lean/RecombinantObese/Recombinant Time Fc-OB Fusion Fc-OB Fusion (days) Vehicle (PBS)Protein Protein 1–2  −.44 +/1.1  −3.6 +/− .41 −1.03 +/− 1.36 3–4 −1.07+/− .13  −6.8 +/− 1.5  −2.7 +/− 1.1 5–6  −.13 +/− 1.1  −9.5 +/− 1.2 −4.9 +/− .95 7–8  −.92 +/− .29 −12.5 +/− 1.6  −7.7 +/− 2.9  9–10    1.6+/− 1.3 −12.6 +/− 1.9  −8.2 +/− 2.9 11–12 −1.98 +/− 1 −13.6 +/− 1.96 −8.6 +/− 2.9 13–14  −5.2 +/− 1.3 −14.6 +/− 1.7 −10.1 +/− 3.6 15–16 −8.6 +/− 0.1 −14.5 +/− 2  −9.4 +/− 2.2 17–18  −8.5 +/− .64 −16.1 +/−1.8  −9.6 +/− 2.99 19–20  −4.1 +/− .99   −16 +/− 1.5 −10.4 +/− 3.3 21–22 −3.9 +/− 3.3 −14.1 +/− 1.1   −10 +/− 4.3

As can be seen, at the end of a 22 day subcutaneous regime, animalsreceiving the FC-OB protein lost over 14.1% of their body weight in leanand 10% of body weight in obese, as compared to animals only receivingthe PBS vehicle and as compared to baseline.

Surprisingly, animals receiving Fc-OB protein up to 22 days continued toloose weight up until 28 days, 4 days after the last injection. Normal(non-obese) CD1 mice administered 10 mg protein/kg body weight/day ofmurine Fc-OB protein via subcutaneous injections stopped at day 22resulted in a 21% loss from baseline weight at day 28 as compared to 14%loss at day 22. Likewise, obese CD1 mice administered 10 mg protein/kgbody weight/day of murine Fc-OB protein stopped at day 22 resulted in a13% loss from baseline weight at day 28 compared to 10% loss at day 22.At day 34 weight loss was maintained at 10% loss in obese mice wherelean mice recovered to 5% loss. Controls in each system from day 22through day 34 averaged from 4% in obese mice and 7% gain in lean mice.

EXAMPLE 2 Use of Human FC-OB Protein Via Subcutaneous Injection in C57Mice

This example demonstrates that injection subcutaneously of human Fc-OBprotein results in weight loss in normal mice. Normal (non-obese) C57mice were administered human Fc-OB protein via subcutaneous injectionsover a 7 day time period. A dosage of 10 mg protein/kg body weight/dayresulted in a 12% (+/−1.3%) loss from baseline weight by the 7th day ofinjections. A dosage of 1 mg protein/kg body weight/day resulted in a8.9% (+/−1.5%) loss from baseline weight by the 7th day of injections.The weight loss with the use of 10 mg protein/kg body weight/day ofhuman OB protein in obese C57 mice resulted in a 1.1% (+/−0.99%) lossfrom baseline weight and a dosage of 1 mg protein/kg body weight/dayresulted in a 2.5% (+/−1.1%) loss from baseline weight, both by the 7thday of injections.

Results

Presented below are the percent (%) differences from baseline weight inC57 mice (8 weeks old):

TABLE 2 Weight Loss Upon Subcutaneous Injection Recombinant Time Fc-OBFusion Recombinant OB (days) Vehicle (PBS) Protein Protein 1–2 .258 +/−1.3  −6.4 +/− 1.6  −2.1 +/− .91 3–4  2.2 +/− 1.1 −12.1 +/− 1.5  −.78 +/−.36 5–6  4.5 +/− 2 −11.5 +/− 1.5  −1.7 +/− .6 7–8  7.0 +/− 2.1 −11.9 +/−1.6    0.1 +/− 1.2  9–10  9.0 +/− 1.9 −11.5 +/− 1.3    7.2 +/− 2.7 11–12  10 +/− 3.8   −9 +/− 1.4   10.9 +/− 2.9 13–14 12.5 +/− 4.4  −9.5 +/−1.6   12.3 +/− 6.4 15–16 11.1 +/− 1.0  −3.0 +/− 1.5   10.3 +/− 3.3 17–1817.2 +/− 3.6    8.0 +/− 1.3   13.3 +/− 3.4

As can be seen, at the end of a day 17 after a 7 day subcutaneous regimeat 10 mg/kg/day, animals receiving the FC-OB protein recovered to 8% oftheir body weight. Animals receiving dosages of 1 mg/kg/day after a 7day subcutaneous regime returned to 6.4% of body weight after 12 days.

These studies also show that during recovery periods from day 7 to day22, after the last injection at day 7, body weight recovery is slower inthe Fc-OB treated C57 mice that with the OB treated mice. This suggeststhat the Fc-OB protein is not cleared as quickly as OB protein therebycausing the extended weight loss effect.

EXAMPLE 3 Dose Response of CF7 Mice Treated with Fc-OB Fusion Protein

An additional study demonstrated that there was a dose response tocontinuous administration of Fc-OB protein. In this study, obese CF7mice, weighing 35–40 g were administered recombinant human Fc-OB proteinusing methods similar to the above example. The results are set forth inTable 3, below, (with % body weight lost as compared to baseline,measured as above):

TABLE 3 Dose Response With Continuous Administration % Reduction in BodyDose Time Weight 0.25 mg/kg/day Day 5 4  0.5 mg/kg/day Day 5 12   1mg/kg/day Day 5 16

As can be seen, increasing the dose from 0.25 mg/kg/day to 1 mg/kg/dayincreased the weight lost from 4% to 16%. It is also noteworthy that atday 5, the 1 mg/kg/day dosage resulted in a 16% reduction in bodyweight. These studies also showed slow weight recovery rates to 0%suggesting that the Fc-OB protein is not quickly cleared thereby causingthe extended weight loss effect.

EXAMPLE 4 Pharmacokinetics of Recombinant Human Fc-OB in CD-1 Mice andDogs

This study demonstrated the pharmacokinetic properties of recombinanthuman met Fc-OB protein in CD-1 mice and dogs. Following intravenous orsubcutaneous dosing at 1 mg/kg/day, serum concentrations of recombinanthuman met Fc-OB protein and human met OB protein were determined by anenzyme-linked immunosorbent assay (ELISA).

In both species, an increase in exposure, as quantified by higher peakserum concentrations and larger areasunder-the-serum-concentration-curve (AUC), was observed when compared torecombinant met-human OB protein. Fc-OB has lower systemic clearancethan recombinant met-human OB protein. This is seen in the lowerclearance and longer half-life of Fc-OB over OB protein. The increase insize causes not only an increase in protein stability, but also adecrease in the efficiency of renal clearance. As a result, Fc-OB iscleared slower from the systemic circulation. The increases in peaktime, peak serum concentrations and AUC for Fc-OB protein are consistentwith lower clearance. Fc-OB protein will yield substantially highersystemic exposure when compared to OB protein. Results are shown inTable 4 below:

TABLE 4 Pharmacokinetic Properties Species CD-1 Mice CD-1 Mice BeagleDogs Route of Administration Intravenous Subcutaneous Subcutaneous OBFc-OB OB Fc-OB OB Fc-OB protein protein protein protein protein proteinDose Level 1 1 1 1 0.5 0.5 (mg/kg) Peak Time (h) 0.14 6 2.8 8 Peak Serum1520 7550 300 1120 Concentration (ng/mL) AUC (ng · h/mL) 1470 3660001230 132000 2200 52500 Half-life (h) 0.491 21.4 0.388 2.13 22.9Clearance 681 2.73 (mL/h/kg)

EXAMPLE 5

This example demonstrates that in normal mice which are not obese and donot have elevated blood lipid levels, administration of humanrecombinant Fc-OB protein results in a lowering of cholesterol, glucoseand triglyceride levels. In addition, this example demonstrates thatthese levels remain low over a three day recovery period.

Normal CD1 mice were administered recombinant human Fc-OB protein viasubcutaneous injections. Blood samples were taken 24 hours after day 23,the last day of injection. As discussed above, the animals lost weightat the dosages administered. As shown in Table 5, the mice hadsubstantial reduction of serum cholesterol, glucose and triglycerides ina dose-dependent fashion when compared to controls:

TABLE 5 Dose Glucose Cholesterol Triglycerides PBS 232.6 +/− 15.1 67.8+/− 3.6 52.6 +/− 3.7  1 mg/kg/day 225.8 +/− 29.1   54 +/− 5.6   43 +/−8.7 10 mg/kg/day 193.2 +/− 21.4 53.4 +/− 5.7   38 +/− 11  1 mg/kg every2 days 242.0 +/− 9.3 52.6 +/− 4.4 40.8 +/− 7.2 10 mg/kg every 2 197.4+/− 27.9 51.4 +/− 5.9 29.8 +/− 6.3 days  1 mg/kg every 3 days 244.8 +/−19.5 60.8 +/− 7.3   54 +/− 7.1 10 mg/kg every 3   188 +/− 31.2 52.2 +/−6.9 26.2 +/− 10.7 days

These data demonstrate that the Fc-OB protein, or analogs of derivativesthereof, are effective blood lipid lowering agents.

EXAMPLE 6

A obese human patient is administered human Fc-OB protein, or analog orderivative for the purpose of weight reduction. The obese patient alsohas elevated levels of blood lipids, including elevated levels ofcholesterol, above 200 mg/100 ml. The patient attains a satisfactoryweight reduction over the course of Fc-OB therapy. A maintenance dose ofFc-OB protein or analog or derivative is administered to the non-obesepatient to maintain lowered blood lipid levels, including loweredcholesterol levels, below 200 mg/100 ml. The dose administered isinsufficient to result in further weight loss. Administration ischronic. Levels of circulating Fc-OB protein or analog or derivative maybe monitored using a diagnostic kit, such as an antibody assay againstthe OB protein (or other antigenic source if applicable).

EXAMPLE 7

A non-obese human patient undergoes coronary bypass surgery or otherinvasive treatment to alleviate advanced stages arterial plaqueformation. After the surgery, the patient is administered a maintenancedose of Fc-OB protein or analog or derivative in order to prevent there-formation of arterial plaque. The dose administered is insufficientto result in weight loss. Administration is chronic. Levels ofcirculating Fc-OB protein or analog or derivative may be monitored usinga diagnostic kit, such as an antibody assay against the OB protein (orother antigenic source if applicable).

EXAMPLE 8

A non-obese human patient experiences hypertension due to restrictedblood flow from clogged arteries. The patient is administered a dose ofFc-OB protein, or analog or derivative thereof sufficient to reducearterial plaque resulting in clogged arteries. Thereafter, the patientis monitored for further arterial plaque formation, and hypertension. Ifthe condition re-appears, the patient is re-administered an effectiveamount of Fc-OB protein, analog or derivative sufficient to restoreblood flow, yet insufficient to result in weight loss. Levels ofcirculating Fc-OB protein or analog or derivative may be monitored usinga diagnostic kit, such as an antibody assay against the Fc-OB protein(or other antigenic source if applicable).

EXAMPLE 9

A human patient experiences gall stones. Either the gall stones are notremoved and the formation of additional gall stones is sought to beavoided, or the gall stones are removed but the gall bladder remains(as, for example, using laser or ultrasonic surgery) and the formationof additional gall stones is sought to be avoided. The patient isadministered an effective amount of Fc-OB protein, analog or derivativethereof to result in prevention of accumulation of additional gallstones or re-accumulation of gall stones. Levels of circulating Fc-OBprotein or analog or derivative may be monitored using a diagnostic kit,such as an antibody assay against the Fc-OB protein (or other antigenicsource if applicable).

EXAMPLE 10

A diabetic human patient desires to use decreased dosages of insulin fortreatment of diabetes. The patient is administered an effective amountof Fc-OB protein, analog or derivative thereof to result in an increasein lean tissue mass. The patient's sensitivity to insulin increases, andthe dosage of insulin necessary to alleviate symptoms of diabetes isdecreased, either in terms of a decrease in the units of insulin needed,or in terms of a decrease in the number of injections of insulin neededper day. Levels of circulating Fc-OB protein or analog or derivative maybe monitored using a diagnostic kit, such as an antibody assay againstthe OB protein (or other antigenic source if applicable).

EXAMPLE 11

A non-obese human patient desires an increase in lean tissue mass fortherapeutic purposes, such as recovery from illness which depleted leantissue mass. The patient is administered an effective amount of Fc-OBprotein, analog or derivative thereof to result in the desired increasein lean tissue mass. Increase in lean tissue mass is monitored usingDEXA scanning. Levels of circulating Fc-OB protein or analog orderivative may be monitored using a diagnostic kit, such as an antibodyassay against the OB protein (or other antigenic source if applicable).

Materials and Methods

Animals

Wild type CD1 mice and (+/+) C57B16 mice were used for the aboveexamples. The age of the mice at the initial time point was 8 weeks, andthe animals were weight stabilized.

Feeding and Weight Measurement

Mice were given ground rodent chow (PMI Feeds, Inc.) in powdered foodfeeders (Allentown Caging and Equipment) which allowed a more accurateand sensitive measurement than use of regular block chow. Weight wasmeasured at the same time each day (2:00 p.m.), for the desired period.Body weight on the day prior to the injection was defined as baselineweight. The mice used weighed 18–22 grams.

Housing

Mice were single-housed, and maintained under humane conditions.

Administration of Protein or Vehicle

Protein (as described below) or vehicle (phosphate buffered saline, pH7.4) were administered by subcutaneous injections or intravenously.

Controls

Control animals were those who were injected with the vehicle alonewithout either Fc-OB fusion protein or OB protein added to the vehicle.

Protein

Sequence ID. Nos. 1, 2 and 3 set forth murine recombinant OB DNA andprotein (FIG. 1), and Sequence ID. Nos. 4, 5 and 6 set forth an analogrecombinant human OB DNA and protein (FIG. 2). As noted aboverecombinant human OB protein as in SEQ. ID. NO. 6 has a lysine residueat position 35 and an isoleucine residue at position 74. Furthermore,the recombinant human protein set forth in Zhang et al., Nature, supra,and PCT publication WO 96/05309 (Dec. 22, 1996) (both incorporated byreference including figures), and the murine and human analogrecombinant proteins of FIGS. 1 and 2 are illustrative of the OB proteinwhich may be used in forming the Fc-OB fusion protein of the presentmethods of treatment and manufacture of a medicament. Other OB or Fcproteins or analogs or derivatives thereof may also be used to form theFc-OB fusion protein.

Herein, the first amino acid of the amino acid sequence for recombinantOB protein is referred to as +1, and is valine, and the amino acid atposition −1 is methionine. The C-terminal amino acid is number 146(cysteine) (see FIGS. 1 and 2). The first amino acid sequence forrecombinant human Fc-OB protein of FIG. 3 is referred to as +1, and isglutamate, and the amino acid at position −1 is methionine. TheC-terminal amino acid is number 378 (cysteine). The first amino acidsequence for the recombinant human Fc-OB protein variant of FIG. 4 isreferred to as +1, and is glutamate, and the amino acid at position −1is methionine. The C-terminal amino acid is number 378 (cysteine). Thefirst amino acid sequence for the recombinant human Fc-OB proteinvariant of FIG. 5 is referred to as +1, and is aspartic acid, and theamino acid at position −1 is methionine. The C-terminal amino acid isnumber 373 (cysteine). The first amino acid sequence for the recombinanthuman Fc-OB protein variant of FIG. 6 is referred to as +1, and isaspartic acid, and the amino acid at position−1 is methionine. TheC-terminal amino acid is number is 373 (cysteine).

Expression Vector and Host Strain

The plasmid expression vector used is pAMG21 (ATCC accession number98113), which is a derivative of pCFM1656 (ATCC accession number 69576)and contains appropriate restriction sites for insertion of genesdownstream from the lux PR promoter (see U.S. Pat. No. 5,169,318 for adescription of the lux expression system). The Fc-OB DNA, describedbelow and shown in FIGS. 3–6, was created and ligated into theexpression vector pAMG21 linearized with restriction endonucleases NdeIand BamHI and transformed into the E. coli host strain, FM5. E. coli FM5cells were derived at Amgen Inc., Thousand Oaks, Calif. from E. coliK-12 strain (Bachmann, et al., Bacterial. Rev. 40: 116–167 (1976)) andcontain the integrated lambda phage repressor gene, cI857 (Sussman etal., C. R. Acad. Sci. 254: 1517–1579 (1962)). Vector production, celltransformation, and colony selection were performed by standard methods,(e.g., Sambrook, et al., Molecular Cloning: A Laboratory Manual, 2dEdition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.)Host cells were grown in LB media.

Fc-OB DNA Construction

The plasmid pFc-A3 (described below) served as the source of sequencefor human immunoglobulin IgG-1 heavy chain from amino acid number 99(Glu) to the natural carboxyl terminus. The human IgG-1 sequence can beobtained from Genebank (P01857).

The human OB sequence is disclosed above as well as Zhang et al.,Nature, supra, and PCT publication WO 96/05309 both incorporated byreference including drawings. The OB DNA was ligated into the expressionvector pCFM1656 linearized with restriction endonucleases XbaI and BamHIusing standard cloning procedures, e.g., Sambrook, et al., MolecularCloning: A Laboratory Manual, 2d Edition, Cold Spring Harbor LaboratoryPress, Cold Spring Harbor, N.Y. The plasmid pCFM1656 carrying the OB DNAsequence served as the source of sequence for the recombinant human OBgene.

The genetic fusing of these two sequences was carried out by the methodof PCR overlap extension (Ho, S. N., et al., Site Directed MutagenesisBy Overlap Extension Using The Polymerase Chain Reaction, Gene 77: 51–59(1989)). The product of the PCR was cleaved with restrictionendonuclease NdeI to create a 5′-cohesive end and with restrictionendonuclease BamHI to create a 3′-cohesive terminus. The vector, pAMG21,was similarly cleaved. A ligation was performed with the fusion fragmentand the linearized vector. Ligated DNA was transformed byelectroporation into the E. coli host strain. Clones surviving onkanamycin (50 μg/ml) selection agar plates were checked for expressionof Fc-OB-sized protein. Plasmid from individual clones was isolated andthe sequence of the gene coding region verified.

When additional modifications of the Fc-OB gene were desired, the PCRtechnique was used again to engineer the changes. Two sets of changeswere performed at the N-terminus of the Fc portion of the fusion protein(SEQ. ID. No. 9) to create the variants SEQ. ID. NOS. 12 and 15. Anothervariant was constructed to introduce four amino acid substitutions toablate the Fc-receptor binding site (leucine at position 15 substitutedwith glutamate), and the complement (C1q) binding site (glutamate atposition 98 substituted with alanine, lysine at position 100 substitutedwith alanine, and lysine at position 102 substituted with alanine (See,Xin Xiao Zheng et. al, J. Immunol. 154: 5590–5600 (1995)). The templatefor this construct was Seq. ID. No. 15 and the resulting variant wasSEQ. ID. Nos. 18.

pFC-A3 Vector Construction

A plasmid, pFc-A3, containing the region encoding the Fc portion ofhuman immunoglobulin IgG-1 heavy chain (See Ellison, J. W. et. al,Nucleic Acids Res. 10: 4071–4079 (1982)), from the first amino acidGlu-99 of the hinge domain to the carboxyl terminus plus a 5′-NotIfusion site and 3′-SalI and XbaI sites, was made by PCR amplification ofthe human spleen cDNA library. PCR reactions were in a final volume of100 ml and employed 2 units of Vent DNA polymerase in 20 mM Tris-HCl (pH8.8), 10 mM KCl, 10 mM (NH₄)₂SO₄, 2 mM MgSO₄, 0.1% Triton X-100 with 400mM each dNTP and 1 ng of the cDNA library to be amplified together with1 uM of each primer. Reactions were initiated by denaturation at 95° C.for 2 min, followed by 30 cycles of 95° C. for 30 s, 55° C. for 30 s,and 73° C. for 2 min. The 5′-primer incorporated a NotI site immediately5′ to the first residue (Glu-99) of the hinge domain of IgG-1. The3′-primer incorporated SalI and XbaI sites. The 717 base pair PCRproduct was digested with NotI and SalI, the resulting DNA fragment wasisolated by electrophoresis through 1% agarose and purified and clonedinto NotI, SalI-digested pBluescript II KS vector (Stratagene). Theinsert in the resulting plasmid, pFc-A3, was sequenced to confirm thefidelity of the PCR reaction.

Methods for Production

The methods below for production have been used to produce biologicallyactive recombinant methionyl murine or human analog OB protein and Fc-OBfusion proteins. Similar methods may be used to prepare biologicallyactive methionyl human OB protein.

Fermentation Process

A batch fermentation process was used. Media compositions are set forthbelow.

A portion of the media consisting of primarily nitrogen sources wassterilized (by raising temperature to 120–123° C. for 25–35 minutes) inthe fermentation vessel. Upon cooling, carbon, magnesium, phosphate, andtrace metal sources were added aseptically. An overnight culture of theabove recombinant murine protein-producing bacteria of 500 mL (grown inLB broth) was added to the fermentor. When the culture optical density(measured at 600 nm as an indicator for cell density) reached 15–25absorption units, an autoinducer solution (0.5 mg/mL homoserine lactone)was added (1 mL/L) to the culture to induce the recombinant geneexpression. The fermentation process was allowed to continue foradditional 10 to 16 hours, followed by harvesting the broth bycentrifugation.

Media Composition:

Batch:

  34 g/L Yeast extract   78 g/L Soy peptone  0.9 g/L Potassium chloride 5.0 g/L Hexaphos  1.7 g/L Citric acid  120 g/L Glycerol  0.5 g/LMgSO₄.7H₂O 0.2 mL/L Trace Metal Solution 0.5 mL/L P2000 AntifoamTrace Metal Solution:

Ferric Chloride (FeCl₃.6H₂O):   27 g/L Zinc Chloride (ZnCl₂.4H₂O):   2g/L Cobalt Chloride (CoCl₂.6H₂O):   2 g/L Sodium Molybdate(NaMoO₄.2H₂O):   2 g/L Calcium Chloride (CaCl₂.2H₂O):   1 g/L CupricSulfate (CuSO₄.5H₂O):  1.9 g/L Boric Acid (H₃BO₃):  0.5 g/L ManganeseChloride (MnCl₂.4H₂O):  1.6 g/L Sodium Citrate dihydrate: 73.5 g/L

Purification Process for Human Fc-OB Fusion Protein

Purification for human Fc-OB fusion protein was accomplished by thesteps below (unless otherwise noted, the following steps were performedat 4° C.). Purification for murine and human OB protein is disclosed inPCT publication WO 96/05309, supra, herein incorporated by reference.

1. Cell paste. E. coli cell paste was suspended in 5 times volumes ofdistilled water. The cells in the water were further broken by twopasses through a microfluidizer. The broken cells were centrifuged at4.2 k rpm for 1 hour in a Beckman JB-6 centrifuge with a J5-4.2 rotor.

2. Inclusion body wash. The supernatant from above was removed and thepellet was resuspended with give volumes of distilled water. The mixturewas centrifuged as in step 1.

3. Solubilization. The pellet was solubilized with 10 volumes of 50 mMtris, pH 8.5, 8 M guanidine hydrochloride, 10 mM dithiothreitol andstirred for one hour at room temperature. The solution is made 40 mMcystamine dihydrochloride and stirred for one hour.

4. The solution from step 3 is added to 20 to 30 volumes of thefollowing refold solution: 50 mM tris, pH 8.5, 0.8 M arginine, 2 M urea,and 4 mM cysteine. The refold is stirred for 16 hours at 8° C.

5. Buffer exchange. The solution from step 4 is concentrated anddiafiltered into 10 mM tris, pH 8.5.

6. Acid precipitation. The solution from step 5 is adjusted to pH 4.75with 50% glacial acid and incubated for 30 minutes at room temperature.The solution is filtered.

7. Cation exchange chromatography. The solution from step 6 is adjustedto pH 7.0 and loaded onto a CM Sepharose Fast Flow column at 10° C. Atwenty column volume gradient is done at 10 mM phosphate, pH 7.0, 0 to0.1 M NaCl.

8. Anion exchange chromatography. The CM elution pool from step 7 isdiluted 5 fold with 5 mM tris, pH 7.5 and loaded onto a Q Sepharose FastFlow at 10° C. A 20 column volume gradient is done at 10 mM tris, pH7.5, 0 to 0.2M NaCl.

9. Hydrophobic interaction chromatography. The Q sepharose pool is made0.75M ammonium sulfate and loaded on a methyl Macroprep hydrophobicinteraction column at room temperature. A 20 column volume gradient isdone at 10 mM phosphate, pH 7.0, 0.75M to 0M ammonium sulfate.

10. Buffer exchange. The pool from step 9 is concentrated as necessaryand dialyzed against PBS buffer.

While the present invention has been described in terms of preferredembodiments, it is understood that variations and modifications willoccur to those skilled in the art. Therefore, it is intended that theappended claims cover all such equivalent variations which come withinthe scope of the invention as claimed.

1. An isolated human leptin fusion protein comprising SEQ ID NO: 9, SEQID NO: 12, SEQ ID NO: 15, or SEQ ID NO:
 18. 2. The fusion protein ofclaim 1 for use in increasing lean tissue mass.
 3. The fusion protein ofclaim 1 for use in decreasing the dose of insulin required for thetreatment of diabetes.
 4. The fusion protein of claim 1 for use indecreasing bone resorption.
 5. The fusion protein of claim 1 for use inlowering serum glucose levels.
 6. The fusion protein of claim 1 for usein increasing insulin sensitivity.
 7. The fusion protein of claim 6,wherein the protein is administered to a human in need thereof.
 8. Thefusion protein of claim 7, wherein the human has diabetes.
 9. The fusionprotein of claim 7, wherein the protein is administered chronically in atherapeutically effective amount.